Multiple choice not randomised in audio test course

in this course: http://www.memrise.com/course/750524/chinesepod-expansion-daily-life-1/

i always get choices from the same lesson… in the learning phase this is counterproductive: i always see only the same lesson items… also in review, the choices are clustered (only items about food in a set, from the food / dwelling lessons, etc)

many thanks